The present invention relates to bleaching compositions useful particularly in the bleaching of fabrics, and also in the treatment of paper pulp and in hard surface cleaning.
While it has been known for some time that compounds which yield hydrogen peroxide in water are effective bleaches, it is also known that the bleaching activity suffers substantially if the temperature of the bleaching solution is under 60.degree. C. The loss of bleaching activity becomes increasingly pronounced as the temperature decreases. It has thus been proposed to use bleaching compositions which are a combination of one or more compounds which yield peroxide in solution, in combination with another compound, known as a "bleach activator", which in solution with the peroxide has the effect of promoting effective bleaching action even at temperatures below the temperature at which the peroxide compound, per se, would suffer loss of activity.
Certain ester compounds have been proposed as such bleach activators. For instance, U.K. Patent No. 864,798 and U.K. Patent No. 836,988, as well as U.K. Patent No. 1,147,871 and U.K. Patent No. 1,382,594, disclose bleaching compositions comprising an inorganic persalt and certain organic carboxylic acid esters. Other esters and their use in association with compounds which generate peroxide in aqueous solution are disclosed in U.S. Pat. No. 4,283,301 and U.S. Pat. No. 4,412,934. The aforementioned U.S. Pat. No. 4,283,301 also discloses certain alpha-omega-alkyldiesters.
Previous attempts to incorporate a quaternary nitrogen moiety into a bleach activator are described in the aforementioned U.K. Patent No. 1,382,594 and U.S. Pat. No. 5,047,577, both of which disclose certain monoesters said to be useful as bleach activators, and U.S. Pat. No. 4,675,131, which discloses a quaternary ammonium compound substituted by three ester groups.
While no particular theory is to be considered to limit the scope of this application, the performance observed in the art is consistent with the formation in solution of a persalt, characterized by the radical --C(O)OOH, formed by a reaction of the peroxide which is formed in solution with the ester group or groups which are present. Thus, some of the aforementioned patents describe the corresponding peracids believed to be formed, while other such peracids are disclosed in U.S. Pat. No. 4,681,592.